The present invention relates to ethylenically unsaturated phosphinic acid and thiophosphinic acid isocyanates and isothiocyanates, and to a process for their preparation. These compounds can be used as starting products for the preparation of photocrosslinkable polymers which are useful, for example, in producing lithographic printing plates and photoresists.
In German Offenlegungsschrift No. 2,053,363, binders are described that result from the reaction between (a) polymers containing hydroxyl or amino groups and (b) at least one saturated alkyl-, alkoxy-, aryl- or aryloxysulfonyl isocyanate. In combination with diazonium salt polycondensation products or photopolymerizable compounds, however, these binders--for example, alkylsulfonylurethane resins--can only be developed in an aqueous-alkaline environment if they have relatively high acid numbers, which impairs the abrasion resistance of the cured layer.
German Offenlegungsschriften Nos. 2,053,364 and 3,036,077 describe photosensitive mixtures which contain, as the binders, reaction products of a polymer comprising hydroxyl groups and alkenylsulfonyl isocyanates. The printing plates produced with these mixtures show an insufficient ink receptivity, such that an unacceptably high number of waste sheets are produced at the beginning of printing. Moreover, the alkenylsulfonyl isocyanates required for the preparation of these binders can only be obtained at great expenditure and high cost, as is evident, for example, from German patent No. 1,297,601.